1. Field of the Invention
The present invention relates to high density cobalt-manganese coprecipitated nickel hydroxide with excellent charge/discharge cycle properties and high temperature stability, which is suitable as a positive electrode active material for a lithium ion secondary battery, and to a process for its production.
2. Background of the Invention
Recently, attempts have been made to add other components to nickel hydroxide used as the starting material for production of lithium nickel oxide, for the purpose of including additional components with lithium nickel oxide for use as the positive electrode active material of lithium ion secondary batteries in order to improve their charge/discharge cycle properties and high temperature stability (JP-A 10-316431).
However, with the conventional process it has been difficult to obtain nickel hydroxide particles containing cobalt and manganese as the additional components while still maintaining density sufficient for current requirements.
The above-mentioned conventional production process gives particles that are inadequate for use in the positive electrode of a lithium ion secondary battery, and thus it has become an important goal to develop high density nickel hydroxide with a high cobalt and manganese content that exhibits a stable high utilization rate at high temperatures and low cycle deterioration.